I see. It's an old model though and they might not have changed out the CMOS battery when they reconditioned it. Then again, you'd expect more problems than this if the CMOS battery is dead.
Replacing it won't hurt though and who knows, it might solve the problem. You can technically do it yourself but it's quite tricky in a laptop. Otherwise, any computer repair shop can do it. Hell, maybe they can check for other issues too while they're at it.